1. Technical Field
Example embodiments of the present invention relate in general to the field of software-defined networking, and more particularly, to a method and apparatus for providing Quality of Service (QoS) applied to a software-defined networking based network.
2. Related Art
In a general network, a single device incorporating a control plane and a data plane operates as a network element. Such network devices form the entire network by distribution, and traffic forwarding is determined through exchange of a control protocol between control planes of each network device, which requires high complexity of the network device. In addition, the inside of each network device is configured using a specific technology of a manufacturer, and is not open to the public in most cases, which leads to an exclusive dependency on the manufacturer when the network device needs to have a new function added thereto or improve a previous function.
OpenFlow allows for development of a new network technology by changing the existing networking technology, which is not open to the public, into an open networking technology. The OpenFlow technology allows the path of packets in a switch to be determined by software run by an external control device, regardless of equipment manufacturers, by separating a packet forward functionality from a control functionality in a network switch (or a router), and providing a standardized protocol for communication between the two functionalities.
Meanwhile, ONF (Open Networking Foundation) established to promote the use and standardization of the OpenFlow technology defines software-defined networking (SDN) technology based on the OpenFlow technology.
The SDN technology separates a control plane from a data plane and mounts most functionalities on a control plane of an SDN controller such that a network device such as a switch or a router has a simple structure to process packets according to a rule provided by the control plane in a unit of a flow through a standardized protocol, such as an OpenFlow protocol, thereby fundamentally resolving network expenses and complexity, and also fundamentally changing the hardware and software technology of the existing networking technology.
However, as for the SDN network, most of the control functionalities are performed by the centralized SDN controller, and thus all rules need to be delivered from the SDN controller when providing Quality of Service (QoS) for packets incoming into a network device, and thus traffic between the SDN controller and the network device is increased and the processing load of the SDN controller is increased.